21223456679 has 2 divisors, whose sum is σ = 21223456680. Its totient is φ = 21223456678.

The previous prime is 21223456673. The next prime is 21223456699. The reversal of 21223456679 is 97665432212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21223456679 is a prime.

It is a super-2 number, since 2×21223456679² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21223456673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611728339 + 10611728340.

It is an arithmetic number, because the mean of its divisors is an integer number (10611728340).

Almost surely, 2^21223456679 is an apocalyptic number.

21223456679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21223456679 is an equidigital number, since it uses as much as digits as its factorization.

21223456679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 47.

The spelling of 21223456679 in words is "twenty-one billion, two hundred twenty-three million, four hundred fifty-six thousand, six hundred seventy-nine".